https://tbj.ui.ac.ir/ Taxonomy and Biosystematics en daily 1 Wed, 01 Apr 2026 00:00:00 +0330 Wed, 01 Apr 2026 00:00:00 +0330 https://tbj.ui.ac.ir/article_30328.html https://tbj.ui.ac.ir/article_30275.html Previous research has demonstrated that morphological variation among riverine populations often reflects local hydrological conditions, habitat structure, and restricted connectivity among drainage systems. Understanding population-level variation is critical for accurate taxonomic resolution and effective fisheries management of widely distributed freshwater species. This study examines morphological differentiation among three riverine populations of Gudusia chapra from the Atrai, Padma, and Brahmaputra rivers of Bangladesh using landmark-based geometric morphometrics. Ninety specimens were analyzed using 15 homologous landmarks, with non-shape variation removed by Generalized Procrustes Analysis (GPA), followed by population-level shape divergence evaluated using Principal Component Analysis (PCA), Relative Warp Analysis (RWA), Canonical Variate Analysis (CVA), and Discriminant Function Analysis (DFA). The first two principal components explained 98.23% of the total shape variance, with PC1 (94.64%) clearly separating the Brahmaputra specimens from those of Atrai and Padma. Pairwise RWA revealed strong morphological divergence between Atrai–Brahmaputra and Brahmaputra–Padma populations, with over 95% of the variance explained by the first two components. UPGMA cluster analysis grouped individuals into three well-defined clusters corresponding to the river systems, with the Brahmaputra population forming the most cohesive cluster and Atrai showing greater within-group dispersion. CVA and DFA further supported significant morphological structuring, with the Mahalanobis and Procrustes distances between populations statistically significant (p<0.01) and an overall classification accuracy of 91.1%. These results demonstrated pronounced population-level shape divergence in G. chapra, likely driven by hydrological heterogeneity and localized environmental pressures. The study provides critical baseline information for stock-based management of this ecologically and commercially important species. https://tbj.ui.ac.ir/article_30189.html This study investigates the morphology of an isolated population of the cyprinid fish Capoeta saadii in the Nesa River within the Lut-Kavir Basin of Iran. Based on an integrated analysis of 52 specimens, the study employed meristic counts, 17 standardized morphometric characters, and seven otolith (asteriscus) morphometric characters. The studied population exhibits distinctive meristic and morphological traits, including 70–86 lateral line scales, 10–14 gill rakers, and disc- or wheel-shaped otoliths with well-developed serrated posterior margins and prominent protuberances. These features morphologically differentiate the Nesa River population from other described populations of C. saadii and related species such as C. fusca. Sexual dimorphism in meristic traits of the studied population was limited; however, it was evident in several morphometric variables and in otolith morphology, including the interorbital distance and the relative dorsal otolith length. Our findings indicate the presence of a geographically isolated population of C. saadii in the Lut-Kavir Basin, which is morphologically distinct and suggests potential adaptations of this riverine population to its desert environment. Robust species delimitation within the C. saadii complex requires confirmation from independent nuclear markers and broader comparative data (e.g., the COI gene), which should be addressed in future studies. The escalating environmental threats to the fragile freshwater ecosystems of the Kavir-e Lut Basin necessitate immediate conservation attention for this population, even as its formal taxonomic status awaits future genetic validation. https://tbj.ui.ac.ir/article_30234.html Acantholimon (Plumbaginaceae) is one of the most diverse genera in Iran with 83 accepted species. Approximately 22 species are documented in the south regions of the country, 16 of which are endemic, mainly restricted to Kerman province. For this study, approximately 45 specimens were collected and analyzed to investigate taxonomic and molecular relationships. Significant taxonomic value was found in characters such as inflorescence type, flower measurements, and calyx morphology/venation. Twenty-two species (45 accessions) from four sections were analyzed using Maximum Parsimony and Bayesian methods based on nrDNA ITS and plastid rpl32-trnL (UAG) sequences. Both datasets yielded similar, highly congruent phylogenetic trees, revealing that the Acantholimon sections in southern Iran are not monophyletic. Notably, the A. scorpius population clustered with individuals from A. spinicalyx, despite morphological differences. This research concludes with the development of a comprehensive diagnostic key and a species distribution map for the southern Iranian taxa. These findings establish a crucial foundation for future studies on the phylogeny, classification, identification, and conservation of the genus. https://tbj.ui.ac.ir/article_30270.html Endemism is a core concept in biogeography, yet terminology describing its different forms remains inconsistent. In particular, no formally defined term exists for taxa whose entire natural distribution is confined to a single geographical or biogeographical unit. This perspective proposes euendemic as a clear and standardized descriptor for complete endemism. The proposed term is strictly spatial and does not imply ecological specialization, evolutionary age, or conservation status. By distinguishing complete endemism from partial forms such as near or subendemism, this contribution aims to improve conceptual clarity and comparability across floristic, biogeographical and conservation studies. Examples from recent regional and global assessments illustrate that complete endemism is already widely applied as an analytical category, despite the lack of an explicit term. Formalizing this condition as euendemic provides a concise vocabulary for a commonly used but previously unnamed concept in biogeography. The proposed terminology is intended for consistent use in floristic checklists, biogeographical syntheses, and conservation assessments. https://tbj.ui.ac.ir/article_30313.html The intertidal zones of Lombok Island, located at the edge of the Wallace Line, represent a biogeographically important transition region that supports high levels of marine biodiversity. This study applied DNA barcoding based on the mitochondrial cytochrome c oxidase subunit I (COI) gene to identify and analyze the phylogenetic relationships of cowries (Gastropoda: Cypraeidae) collected from three coastal localities (Kayangan, Sambelia, and Sekotong). A total of seven cowrie species were confirmed, namely Bistolida hirundo (Linnaeus, 1758), Erronea errones (Linnaeus, 1758), Mauritia arabica (Linnaeus, 1758), Monetaria annulus (Linnaeus, 1758), M. moneta (Linnaeus, 1758), Naria boivinii (Kiener, 1844), and N. erosa (Linnaeus, 1758). In addition, one species from the family Ovulidae, Calpurnus verrucosus (Linnaeus, 1758), was included as the outgroup. BLAST analyses revealed high similarity values (>98%) with reference sequences in GenBank, validating the reliability of species-level identification. Genetic distance analysis using the Kimura 2-parameter (K2P) model showed clear interspecific divergence (0.114–0.232), supporting the presence of a “barcode gap” among examined taxa. Phylogenetic reconstruction using the Maximum Likelihood method with bootstrap support generally exceeding 90%, indicating low interpopulation genetic differentiation and highlighting effective larval dispersal across oceanic regions. Nucleotide composition analysis further confirmed a consistent AT-rich bias (61–63%) typical of gastropod mitochondrial genomes, with subtle interspecific variation potentially useful for molecular diagnostics. This research provides the first DNA barcoding and phylogenetic assessment of cowries from Lombok, enriching the genetic database of Cypraeidae and offering essential baseline data for conservation, biogeographic, and evolutionary studies in the Indo-Pacific marine hotspot. https://tbj.ui.ac.ir/article_30262.html Leaf stomatal morphology is a key determinant of plant adaptation to environmental stress, particularly drought. This study conducted a comprehensive assessment of stomatal traits across 26 grape cultivars (Vitis vinifera L.) cultivated in the semi-arid region of Qazvin, Iran. Over two growing seasons (2022–2023), epidermal impressions were prepared using the nail polish technique, and parameters including stomatal density, dimensions, complex type, surface coefficient, shape coefficient, and percentage of occupied area were quantified using light microscopy and image analysis software. Multivariate analyses (MANOVA, PCA) and univariate tests (ANOVA, FDR-corrected correlations) were employed. Results revealed considerable diversity in all measured traits. Cultivar 'Ahmadi' exhibited the largest stomata (polar length: 41.29 µm, equatorial width: 29.25 µm) and the lowest density (39 stomata per unit area), whereas 'Karreh Ruye' showed the highest density (124 stomata). PCA identified two independent axes of variation: stomatal size (explaining 69.6% of variance) and density-coverage (17.7%). Although an inverse trend between size and density was observed, the correlation was not statistically significant after FDR correction. Cluster analysis grouped cultivars into two main clusters, reflecting distinct morphological strategies: large stomata with low density versus small stomata with high density. The predominant stomatal complex type was anomocytic. The findings indicate that stomatal traits, particularly the size-density combination, could serve as preliminary morphological markers for screening cultivars with putative drought adaptation. Cultivars such as 'Ahmadi', which exhibit a morphology often associated with water conservation strategies, warrant further physiological evaluation under water-limited conditions. https://tbj.ui.ac.ir/article_30315.html Psephellus, a genus of the tribe Cardueae in the family Asteraceae, comprises 114 currently accepted species. In Iran, the genus includes 14 species in eight sections, of which seven are endemic. For the taxonomic study of Psephellus sect. Psephelloidei (Boiss.) Wagenitz & Hellwig, extensive collections were conducted across its distribution area in northwestern Iran. Plant specimens were collected using conventional methods and identified based on reliable taxonomic sources. Moreover, numerous specimens deposited in different herbaria were examined. As a result, Psephellus gilanicus (Bornm.) Wagenitz subsp. qazvinicus Negaresh, a new subspecies of P. sect. Psephelloidei from Qazvin province, northwestern Iran, is described and illustrated. It resembles P. gilanicus subsp. gilanicus but differs from it in having a few-stemmed habit, the whole plant usually grayish, undivided median cauline leaves, straw-coloured or whitish-pale brown median and inner appendages, white flowers, and oblanceolate achenes ca. 7 × 3–3.5 mm, slightly covered with short hairs. The new taxon is notably characterized from other members of P. sect. Psephelloidei by its white flowers. In addition, the geographical distribution of the new subspecies and the closely related taxon is presented and mapped. https://tbj.ui.ac.ir/article_30321.html Current research investigated twenty barley genotypes under rainfed conditions to examine variability in yield, its components, and morphological traits, while identifying key selection criteria. Biomass-related traits, such as biological yield and straw weight, displayed high variability, whereas thousand-seed weight showed minimal variation. Traits such as seed yield per plant, seed number per plant, and tiller number per plant exhibited moderate variability, highlighting their potential contribution to yield differences. Phenotypic correlation analysis revealed that yield was strongly linked to biomass yield and thousand-seed weight, suggesting that both source and sink components play essential roles in yield formation. Genotypic correlations were generally weaker than phenotypic correlations, reflecting the influence of environmental factors. However, thousand-seed weight, seed number per plant, and fertile tiller number consistently showed positive associations with yield, indicating their genetic stability and value for indirect selection. Factor analysis identified five independent factors. The first factor included biomass yield, straw weight, and seed yield, whereas the second factor represented seed yield per plant and seed number per plant. The third factor identified low-tillering genotypes, while the fourth factor reflected smaller seed size. Finally, the fifth factor captured variation in plant height. These factors emphasize the multifaceted nature of yield determination, with distinct separations between vegetative growth, reproductive efficiency, and plant size. Based on these findings, genetic improvement for seed yield under rainfed conditions should prioritize thousand-seed weight, seed number per plant, and fertile tiller number, while optimizing plant height.